Connector socket for spark plugs

ABSTRACT

Connector socket for spark plugs to be connected to the firing conductor of an inserted spark plug, and having a body element made of a thermosetting plastic and having fingers which engage firmly the insulation of the firing conductor whose end is inserted in the body element, the body element further having an annulus defining a socket opening for receiving a spark plug; the fingers extend from that annulus; a sleeve-like casing, also made of thermosetting material, receives the body element and is fastened thereto; an elastomeric filling and sealing means fills all spaces between the casing and the body element and projects beyond the body element to provide a complete sealing annulus around the conductor; the sealing means further provides a washer-like constriction of the socket opening, slightly smaller in diameter than the diameter of the spark plug to be inserted; an electrical shield is inserted between casing and body element.

United States Patent [191 Rohrig et al.

[451 Apr. 9, 1974 CONNECTOR SOCKET FOR SPARK PLUGS [73] Assignee: Kabel und Metallwerke Gutehoffnungshutte Aktiengesellschaft, Postfach Hannover, Germany [22] Filed: Aug. 24, 1972 [21] Appl. No.: 283,623

[30] Foreign Application Priority Data Aug. 25, 1971 Germany 2142554 [52] US. Cl. 339/26, 339/143 S, 339/213 S [51] Int. Cl HOlr 13/44 [58] Field of Search 339/26, 27, 213, 116, 143, 339/111, 136, 140, 59, 60, 61; 174/74, 77

3,376,541 4/1968 Link 339/143 S 3,044,037 7/1962 Honig.... 339/116 C X 2,553,114 5/1951 Sailler 339/26 X Primary ExaminerBobby R. Gay Assistant Examiner-Terrell P. Lewis Attorney, Agent, or FirmSmyth, Roston & Pavitt 5 7 ABSTRACT Connector socket for spark plugs to be connected to the firing conductor of an inserted spark plug, and having a body element made of a thermosetting plastic and having fingers which engage firmly the insulation of the firing conductor whose end is inserted in the body element, the body element further having an annulus defining a socket opening for receiving a spark plug; the fingers extend from that annulus; a sleevelike casing, also made of thermosetting material, receives the body element and is fastened thereto; an elastomeric filling and sealing means fills all spaces between the casing and the body element and projects beyond the body element to provide a complete sealing annulus around the conductor; the sealing means further provides a washer-like constriction of the socket opening, slightly smaller in diameter than the diameter of the spark plug to be inserted; an electrical shield is inserted between casing and body element.

4 Claims, 4 Drawing Figures CONNECTOR SOCKET FOR SPARK PLUGS BACKGROUND OF THE INVENTION The present invention relates to a connector socket element for spark plugs as they are used in internal combustion engines. The socket element is affixed to the end of an insulated electric conductor for the firing voltage and includes an electrical contact which is connected to the conductor and serves as contact-making element with the plug pin of the spark plug.

Connector socket elements of the type referred to above are used today in numerous configurations, and they are almost exclusively made of thermosetting material. These known socket elements are usually quite strong, but, unfortunately, they are often brittle and break rather easily rendering the respective spark plug inoperative. Moreover, the socket elements are often quite stiff so that gaps may appear between the spark plug and connector socket on one hand and the conductor for the firing voltage on the other hand; moisture may penetrate into that gap and reach the area of contact making. Moreover, the conductor may readily kink and even break where extending from the connector socket element if not handled carefully.

DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a connector socket element for spark plugs which is easy to make, protects the internal electrical connector against moisture and prevents kinking of the conductor.

In accordance with the preferred embodiment of the invention, it is suggested to provide a body of a heat resisting thermosetting plastic which firmly grips the insulation of the conductor on one end of the body, while the other end of the body has a socket-defining opening for receiving the spark plug. The body is completely encased (except for axial end openings) by means of a casing which engages the body in the central region and is also made of thermosetting material. Spacer filling and sealing element or elements are provided to fill all spaces between casing and body and aremade of elastomeric material. Moreover, the latter element or elements project beyond the body so as to enclose the insulation of the conductor, and it or they protrude into the receiving opening of the body so that the resulting opening is slightly too small for the spark plug. Thus,

the spark plug, when inserted, is tightly sealed as far as the inserted portion is concerned.

The body may be constructed as an annulus defining the socket cavity, and fingers extend from that annulus for gripping the inserted conductor. Preferably, body and casing are fastened to each other, and an electrically shielding sleeve may be inserted between body and casing, around the socket opening and cavity.

The construction in accordance with the invention has the advantage that the elastic sealing and filling element tightly encloses the conductor and seals the inserted spark plug 'so that the interior of the socket element is well protected against moisture, and the conductor is protected against kinking and breaking. On the other hand, the connector element as a whole has sufficient strength due to the use of conventional material for the body and its casing. As there are no longer unfilled gaps leakage currents will not result upon application of a high firing voltage to the conductor.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention, it is believed that the invention, the objects and features of the invention and further objects, features and advantages thereof will be better understood from the following description taken in connection with the accompanying drawings in which:

FIG. 1 is a section view of a connector socket element in accordance with the preferred embodiment of the invention;

FIG. 2 is a section along lines II II in FIG. 1, and indicating the section plane I I for the view of FIG.

FIG. 3 is a section view of a component in the element of FIGS. 1 and 2; and

FIG. 4 is a front view of the component shown in FIG. 3 as indicated therein by lines 4 4, and showing also the section plane 3 3 for FIG. 3.

DESCRIPTION OF THE DRAWINGS Proceeding now to the detailed description of the drawings, the connector socket element, as illustrated in FIG. 1, is connected to a conductor 1 which is insulated and applies firing potential to a spark plug, to be inserted in the socket element. The socket element has a somewhat tubular body 2 made of a thermosetting plastic material. Body 2 is received in a sleeve-like casing 3, which is likewise made of thermosetting plastic material. All gaps between body 2 and casing 3 are filled by the filler and sealing element 4, made of elastomeric material.

A resistor 5 is received in the hollow interior of body 2 and is connected to conductor 1. A contact element is also provided in body 2 and connected to the resistor 5. The contact 6 will make contact with the connector pin of a spark plug when inserted in socket opening 10 of body 2. A metal sleeve 7 surrounds opening or socket cavity 10 and projects beyond the body for obtaining electric shielding. FIGS. 3 and 4 show body 2 in greater detail. The body has an annular end 1 1 which defines the socket cavity and opening 10. Finger elements 12 project axially from annulus 11 having corrugations 8 at one end each of the respective inwardly facing edges of the fingers. There are four such fingers 12 arranged in a star configuration. The respective opposite edge of each flat finger is provided with a pawllike step 9. casing 3 is provided internally with a shoulder gripping behind the steps 9 when slipped over body Upon comparing FIGS. ,1 and 3 further, one can see that the corrugations 8 of the fingers l2 grip the insulation of the conductor 1. The slipped over casing 3 urges the fingers into a firm conductor holding and gripping position.

Upon assembling the element, the casing 3 is first slipped onto conductor 1 and temporarily held out of the way of the conductor end. Next, the resistor 5 is connected to the conductor 1 through soldering or the like. The other end of the resistor may already carry the contact sleeve 6. Next, body 2 is stuck onto the conductor 1 so that the resistor is received in the hollow interior of body 2, while contact sleeve 6 projects into the socket cavity 10. Thereafter casing 3 is shifted over the body 2 and into the position shown in FIG. 1. The central portion of casing 3 (section line II II runs through that portion) abuts directly the fingers 12. The

steps 9 of fingers l2 latch behind the shoulder in casing 3, to fasten the casing to the body element 2. This provision serves as tension relief for the socket element as well as for the conductor.

After placing the casing 3 onto body 2, the sleeve 7 is slipped in between the annular portion 11 or body 2 and the surrounding portion of casing 3. It should be mentioned, however, that the sleeve 7 is not an essential part, other shielding may be provided for or not needed at all. Finally, all remaining cavities are filled through injection with an elastomeric plastic which upon curing establishes an integral filler 4. Particularly, the gaps between fingers l2 and the space around resistor are filled. The material 4 projects beyond the fingers l2 and provides for complete encapsulation around conductor 1 at that end of the plug constriction (annulus 41). The elastomeric part 4 now surrounds the conductor end where not gripped by the fingers l2, and integrally seals the conductor insulation to the socket element as a whole. As part 4 is formed inside, any cavities and gaps between casing 3 and body 2 are also filled with the elastomeric material so that the conductor end is tightly sealed, and the gripping fingers are embedded in elastic filler and sealing material.

Part 4 provides for both, protection against penetration of moisture and protection against wire kinking and breaking.

As the body 2 has flattened sides at annulus ll, elastomeric material will also flow in the space between body 2 and easing 3 and will even form an annular washer-like portion 42 that narrows the entrance to socket opening 10. The diameter of this constricted opening, as defined by annulus 42, is somewhat smaller than the diameter of the spark plug to be inserted so that annulus 42 can sealingly grip and engage the spark plug surface to seal the interior of body 2 against moisture penetration also from this end. As now all internal cavities of the assembly 1 2 3 5 are filled with elastomeric material, there will be no longer any leakage current of the type that does destroy the plug elements of the prior art.

The invention is not limited to the embodiments described above but all changes and modifications thereof not constituting departures from the spirit and scope of the invention are intended to be included.

We claim:

l. Connector socket for spark plugs to be connected to the firing'conductor of an inserted spark plug, comprising:

body clement made of a thermosetting plastic and constructed to engage firmly the insulation of the firing conductor whose end is inserted in the body element and terminating therein, the body element further having a socket defining opening for receiving a spark plug in alignment with the conductor, the opening being separated from the interior of the body in which the conductor end is received;

a sleeve-like casing made of therrnosetting plastic,

receiving the body element substantially in its entirety and engaging the same directly in a central position; and

a coherent, single element elastomeric filling and sealing means, filling all spaces inside of the casing as between the casing, the body element and the conductor as inserted for preventing any glow dis charge anywhere in said spaces, and projecting beyond the body element adjacent the conductor to provide a complete annulus around the conductor, the sealing means further providing a construction of the socket opening, slightly smaller in diameter than the diameter of the spark plug to be inserted.

2. Connector socket as in claim I, the body element having an annular portion defining the socket opening, and plural fingers extending from the annular portion in axial direction but being spaced by gaps around the circumference of the conductor to grip the insulation of the firing conductor, the elastomeric sealing means extending into the gaps between the fingers, the annulus of the sealing means extending beyond the axial ends of the fingers as extending from said annular portion.

3. Connector socket as in claim 1, and including an electrically shielding sleeve inserted in between the body element and the casing and surrounding the opening, the latter sleeve projecting beyond the body in direction of the spark plug to be inserted in the opening.

4. Connector socket as in claim 1 and including means on the body element and on the casing for mutual fastening. 

1. Connector socket for spark plugs to be connected to the firing conductor of an inserted spark plug, comprising: a body element made of a thermosetting plastic and constructed to engage firmly the insulation of the firing conductor whose end is inserted in the body element and terminating therein, the body element further having a socket defining opening for receiving a spark plug in alignment with the conductor, the opening being separated from the interior of the body in which the conductor end is received; a sleeve-like casing made of thermosetting plastic, receiving the body element substantially in its entirty and engaging the same directly in a central position; and a coherent, single element elastomeric filling and sealing means, filling all spaces inside of the casing as between the casing, the body element and the conductor as inserted for preventing any glow discharge anywhere in said spaces, and projecting beyond the body element adjacent the conductor to provide a complete annulus around the conductor, the sealing means further providing a construction of the socket opening, slightly smaller in diameter than the diameter of the spark plug to be Inserted.
 2. Connector socket as in claim 1, the body element having an annular portion defining the socket opening, and plural fingers extending from the annular portion in axial direction but being spaced by gaps around the circumference of the conductor to grip the insulation of the firing conductor, the elastomeric sealing means extending into the gaps between the fingers, the annulus of the sealing means extending beyond the axial ends of the fingers as extending from said annular portion.
 3. Connector socket as in claim 1, and including an electrically shielding sleeve inserted in between the body element and the casing and surrounding the opening, the latter sleeve projecting beyond the body in direction of the spark plug to be inserted in the opening.
 4. Connector socket as in claim 1 and including means on the body element and on the casing for mutual fastening. 